1. Field of the Invention
The invention relates to a wind turbine apparatus for generating electrical energy by means of wind energy, especially relates to a wind turbine apparatus having a variable pitch angle mechanism of wings.
2. Background Art
Conventionally, a wind turbine apparatus having a generator is known that it generates electrical energies by changing wind energies changed to rotation powers through wind wheel, and the rotation powers is transmitted to the generator connected with the wind wheel.
There are some types of this kind of wind turbine apparatus, such as the speed-increasing type, which generate electricity by increasing the rotation speed of a wind wheel by using speed-increasing device having a gear mechanics, and such as the direct type, which generate electricity without increasing the rotation speed of the wind wheel and transmit the rotation. The latter is more excellent than the former in the point that the speed-increasing device having complex mechanisms becomes unnecessary, even though a larger-scale (large diameter) generator should be needed.
Moreover, a wind turbine apparatus having changeable a pitch mechanism is known, which adjust a rotational speed of the wind wheel to a suitable rotational speed for a generator by changing pitch angles of braids of the wind wheel according to the speed of the wind.
Then, a wind turbine apparatus having the main shaft supporting hub at its top end, and supporting a generator rotor is also known as one of above-mentioned direct type having the changeable pitch mechanism (For instance, see patent document 1 and patent document 2).
However, since the generator rotator is supported on the main shaft, the main shaft had to be designed long, and weight became heavy, so troubles of its heavy weights and bad assembling properties are found in the generator disclosed in the patent document 1 and 2. Moreover, since the wind turbine apparatus device has a structure to support heavy loads such as a wind wheel and a generator on the tower of prescribed height, it is originally requested to lighten the wind turbine apparatus as much as possible.